I dunno. I realized a long time ago that it is NOT useful to try to port "Arduino" to every "worthy" processor that exists. Nor is it particularly useful to design Arduino-compatible boards with each conceivable hardware improvement. For one things, these dilute the focus of the arduino user community. (for instance, I sorta want a 32MHz Xmega-based arduino with a programmable FTDI VNC2 doing the USB connectivity. (USB device AND host!) But I'm not sure how it'd be better than a Due or ChipKIT.)
I don't see how a 16-core parallel processor can be "arduino compatible" at the sw layer in any meaningful way 
Arduino is supposed to be SIMPLE; I regard products like Galileo to be somewhat fundamentally "misguided." (But, what do I know! I could have sworn that RPi would not have been as successful as it has been.)
The Prop-2 specs cannot be ignored
They can certainly be ignored until after the chip actually exists.
I'm not sure how a chip with "only" 512k memory (only 32k on each COG) is supposed to do a meaningful job of 1080p video (~2Mpixel); All sprites all the time? (And I'm not sure how you integrate video into the arduino environment at all.)
All that said, Parallax would be foolish not to create a board with the infamous "Arduino pinout."